1. Field of the Invention
The present invention relates to a camera system, and more particularly relates to a camera system with which a plurality of images can be displayed side by side.
2. Background Information
Single-lens reflex digital cameras have become tremendously popular in recent years. With a single-lens reflex digital camera, when an optical viewfinder is used to view a subject, the light incident on the imaging optical system is reflected by a reflecting mirror disposed along the optical path, and is guided to the viewfinder optical system. As a result, the subject image is converted by a pentaprism or the like into an erect image before being guided to the viewfinder optical system. This allows the user to view the subject image formed by the imaging optical system through the optical viewfinder. Thus, the reflecting mirror is usually disposed along the optical path.
Meanwhile, when an optical image of the subject is converted into an image signal, the reflecting mirror is retracted from the optical path so that the light from the imaging optical system will be incident on an imaging element. As a result, opto-electric conversion is performed by the imaging element, and image data about the subject is obtained. When imaging is complete, the reflecting mirror is returned to its home position along the optical path. With a single-lens reflex camera, this operation of the reflecting mirror is the same regardless of whether the camera is a conventional silver halide camera or a digital camera.
However, when the home position of the reflecting mirror lies in the optical path, the light from the imaging optical system is not incident on the imaging element. Therefore, in the case of a digital camera, with the above-mentioned system, a monitor photography mode, in which the user uses the liquid crystal monitor to view the subject, cannot be achieved, and a camera system such as this is inconvenient for a beginner unaccustomed to photography.
In view of this, as discussed in Japanese Laid-Open Patent Application 2001-125173, a single-lens reflex digital camera has been proposed with which a liquid crystal monitor can be used during image capture. With this camera system, in monitor photography mode, the reflecting mirror is retracted from the optical path and the light from the imaging optical system is incident on the imaging element. This allows the subject to be viewed on the liquid crystal monitor.
Also, the imaging element of a single-lens reflex digital camera is generally larger in size than the imaging element of an ordinary compact digital camera. Therefore, when an optical image of the subject is formed on the imaging element, a smaller area is in focus, and the subject field depth tends to be shallow. Therefore, with a single-lens reflex digital camera, it is important to adjust the aperture and confirm the subject field depth.
In view of this, as discussed in Japanese Laid-Open Patent Application H6-6807, a camera system has been proposed with which a plurality of images captured under different photography conditions, for example, can be displayed side by side.
However, if the user changes the framing, or if the subject moves, when the two images are compared, the composition can be quite different between the reference image acquired ahead of time and the comparative image serving as a live image, so that the images cannot be compared. Thus, a conventional camera system lacked convenience in comparing images in some situations.